Australia's hands tied as whaling war deepens

An international law expert says Australia does not have undisputed jurisdiction to enforce its laws against Japanese whalers and anti-whaling protesters in the Southern Ocean.

Authorities are calling for calm after an anti-whaling protester's ribs were broken when a Japanese ship sheared the bow off the Sea Shepherd trimaran Ady Gil yesterday.

Sea Shepherd crew members on board the $1.5 million carbon fibre speedboat say they were forced to hold on for their lives as the 52-metre Shonan Maru 2 crashed into their vessel.

Sea Shepherd says the Ady Gil was motionless in the water and the Shonan Maru 2 swerved to hit it.

But Japan's Institute for Cetacean Research says its ship was trying to take evasive action when the incident happened.

The Federal Government has come under pressure to send planes and boats to reassert Australian law and authority in the waters off Antarctica.

But Dr David Leary from the University of New South Wales says only a small number of countries recognise Australia's claim to Antarctic territories and any intervention could backfire.

"From Australia's point of view, the risk of us seeking to enforce our laws in the waters off Antarctica is that if this ever ends up before the International Court of Justice or the International Tribunal for the Law of the Sea, we may end up with a situation where we have a finding by an international court that says our claim to our Antarctic territory is not legitimate," he said.

"That's the ultimate worst-case scenario."

Sea Shepherd says the incident took place at 64 degrees and 3 minutes South and 143 degrees and 9 minutes East in the waters of the Australian Antarctic Territory.

No investigation

The Australian Transport Safety Bureau (ATSB) says at this stage it will not be investigating the clash because it believes the incident was a deliberate action by one or both parties.

"It's not a matter of a safety lapse, so there's no safety lesson to be learnt," a spokesperson said

The ATSB says its hands are also tied because neither vessel in the incident is registered in Australia.

The Ady Gill is a New Zealand-registered boat

The University of Queensland's Professor Michael White says an inquiry is needed to establish what happened.

"There is provision, both under Australian law and Japanese law, to hold an inquiry into this collision," he said.

"I wouldn't be at all surprised if the Australian Transport Safety Bureau, which is the one that conducts the inquiries, doesn't start one.

"And I wouldn't be at all surprised if the Japanese equivalent doesn't start one as well, because it is a major collision at sea."

Sea Shepherd's Chris Aultman is adamant the Ady Gil was not at fault.

"At the time of the collision, the vessel was dead in the water. It was motionless," he said.

"The Shonan Maru just must have seen a very suitable target and took upon itself to strike the vessel."

But the spokesman for the Institute of Cetacean Research in Tokyo, Glenn Inwood, has contradicted Sea Shepherd's account of the clash.

"The [Ady Gil] skipper puts the boat into full sting to try to cut the Shonan Maru off," he said.

"You can see that the Shonan Maru is moving to port to try and avoid a collision and there's no avoiding the collision with the Ady Gil.

"It's a fast boat, she heads off full steam in front of it and miscalculates. So it's no wonder that it came to the grief that it has."